# GazeClient

A Javascript library to subscribe to local gaze data streams in the OTH/UR Eye-Tracking Classroom. Packed and compressed library files can be found in `/build`.

GazeClient connects to a running [GazeServer](https://lab.las3.de/gitlab/eye-tracking-classroom/gaze-server.cs) instance on the local machine and publishes gaze data from the currently tracked user. Websockets are used to connect client and server.

## Usage

**Add the library to your application:**

```
<script type="application/javascript" src="gazeclient.js"></script>
```

**Create a client and subscribe to gaze events:**

```
var gclient = new GazeClient();
gclient.addEventListener("gazeDataAvailable", function onGazeDataAvailable(event) {
	console.log(event);
});
```

**Connect to a running gaze data server by providing a valid URL:**

```
gclient.connect("ws://localhost:8001/gaze");
```

### Events

| Event | Type  | Description  | Data |
|---|---|---|---|
| ConnectionOpenedEvent  | connectionclosed  | Invoked when client successfully connected to server.  | - |
| ConnectionClosedEvent  | connectionclosed  | Invoked when client lost connection to server. | - |
| ConnectionErrorEvent  | erroroccurred  | Invoked when an error occurred during server client communication. | - |
| DataEvent | dataavailable  | Invoked when new gaze data from eye-tracker is available.  | On-display (x,y) coordinates for both eyes |

## Build

**Prerequisite**

- node.js

To build a current version of this library run `npm install` and `npm run build`. The client library is packed with [rollup](https://rollupjs.org/guide/en/), compress with [uglify-es](https://github.com/mishoo/UglifyJS2/tree/harmony) and copied to `build/` and `demo/`.